Web pages are frequently moved. Because of this, links to them on other pages can become stale. All web users have had the frustrating experience of attempting to link to a page of interest, only to receive an error message stating that that the page cannot be found. Very often, this is not because the page no longer exists, but because it has been moved to a new server or the like. Furthermore, if it is in fact the case that the page no longer exists, the user is not provided with any resources for obtaining information similar to that provided by the page. Links to web pages in the form of Uniform Resource Locators (URLs) become useless if a web page is moved within a given site, moved to a completely different site or eliminated altogether.
What is needed is a more flexible and long lasting mechanism for locating the information represented by a web page.